[s-cars] AAN 101

[Fred Munro]

Hi Jouko;

A bad cam sensor is a known issue on the UrS cars, although the usual
symptoms are hard/no start. It's easy to check the cam timing - pull the top
t-belt cover, line up the TDC mark on the flywheel (assuming it's there - my
'94 S4 doesn't have a marked flywheel for some reason) and check the timing
mark on the cam. A dimple cast in a cam gear tooth lines up with an arrow
cast in the head.
Another common cause of misfire is a bad POS (Power Output Stage, there are
two and they fire the ignition coils)
Checking the TP is not quite as straightforward. The ubiquitous VAG 1551
Scan Tool is used to check the output of the TP at idle (5 - 10 degrees) and
WOT (92 - 102 degrees).
You can check the voltage to the TP. There are two measurements - connect to
terminals 1 & 2, and then to terminals 3 & 4 on the wiring harness, the
voltage should be 4.5 - 5.5 volts in both cases.
You can also check the TP sensor resistance. Resistance between terminals 1
& 2 on the TP connector should be 1500 - 2600 ohms. Slowly open the throttle
to WOT. The resistance should increase to 3600 ohms max. Repeat with
terminals 2 & 3. Starting resistance should be 750 - 1300 ohms. WOT
resistance is 3600 ohms max.
Congratulations on the '92 S4! Since you are in Georgetown, you should check
out the SOS (Southern Ontario S-cars) club. They're a great bunch of guys
and meet monthly at the Bavarian Outpost for some Audi talk and beer. I'm a
member, but I don't get to many meetings - it's a long drive for some
bratwurst. I do get to some of the ice races, though, since they are held in
my neck of the woods. The club has a mailing list on yahoogroups -
SOS-cars at yahoogroups.com

HTH

Fred Munro
'94 S4
----- Original Message -----
From: "Jouko Haapanen" <joukoh at sympatico.ca>
To: <s-car-list at yahoogroups.com>; "q-list" <quattro at audifans.com>; "W-T
Audifans" <w-t_audifans at yahoogroups.com>
Sent: Saturday, October 13, 2001 8:15 PM
Subject: [s-cars] AAN 101


> So today I got my initiation in AAN diagnosis.  The patient - 1994 S4,
> 192 000km.  The patient lacked boost , ran poorly and misfired.  I was
> told that the turbo was toast when I bought it.  So this morning I
> pulled the intake boot off the turbo and lo and behold, the compressor
> wheel spins freely and no excessive radial or axial play was felt my
> my highly calibrated fingertips.  Off came the valve cover and I found
> the proverbial fish tank in the plug recesses.  Dried it up, pulled
> the plugs and and they looked like hell.  A quick look on my shelves -
> no plugs of the correct type - a minutes drive down to Four Star
> Motorsports where Dan Sprongl had plugs on the shelf.  Hey, it's going
> to be nice living in Georgetown. Mike Hopton dropped in just as I was
> leaving, what a small world.  Back to the shop, plugs in, Mike drops
> in, clean up the ground points for the coil packs (thanks Mike) and
> try it again.  Now it runs much smoother, still a definite misfire,
> though, and still no power.    Mike and I somehow couldn't pull codes
> at this point so I kept on poking.  A look underneath the car, pull
> the accordion hose off the steel crossover pipe-IC intersection and
> check it out.  Healthy.  Clean hose, hose back on.  Frustration
> setting in, thinking of the coil packs - maybe a couple are dead?  Try
> to pull codes again and out they come (thanks Scott for your helpful
> site once again, code descriptions from your site):
>
> 2212
> Throttle potentiometer,
> short circuit to + or to ground,moisture or corrosion in harness
> connector
> Check throttle potentiometer resistance from idle to full throttle.
> Symptom: Lack of power or boost pressure is not attained
>
> 2113
> Hall sensor in distributor (3B, early AAN engines) or
> camshaft position Hall Effect sensor on later AAN (S4/S6 engine).
> Distributor alignment, faulty sender,
> Mis-located sensor & distributor, Cam timing possibly incorrect on AAN
> engine
>
> Any ideas as to whether they could be related?  2212 seems fairly
> straightforward, I'll poke around at that tomorrow.  It would help to
> have that Bentley - all my VW and UrQ manuals aren't much help here.
> What resistance range am I looking for on the throttle potentiometer?
> How many connectors are there (car is at work - I'm back home now) and
> which ones do I measure across?
>
> 2113 spooks me a bit.  Could I have a timing issue -belt that is off a
> tooth?
>
> The one nice thing about the UrS4 is that compared to the UrQ, there
> is a ton of space to work underhod.  Still, it would help if instead
> of engineering I'd studied to be a gynecologist.
>
> Jouko Haapanen
> Georgetown, ON
>
>
>
>
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